LONG-TERM MORPHOLOGICAL CHANGES AND HYDRODYNAMICS OF TIDAL DOMINANT COASTAL ZONE IN THE HAI PHONG ESTUARY, VIETNAM

Abstract

The paper presents the investigation of morphological changes and simulation of circulation in the Hai Phong area, Vietnam using remote sensing and measured data for a period of 1965-2005. During this period, the shoreline and sea bottom relief have changed considerably. The circulation and sediment transport process were simulated by developing a modeling system. In the system, three-dimensional thermo-dynamic primitive equations were used to investigate current velocity, water level, and the sediment transport. A special computing procedure was applied to the river boundaries because the tidal range in the area is approximately 4 m. In addition to the model study, a record of field survey for the wave climate is presented in a period from 2005 to 2006. The result suggests that the wave energy is small throughout a year, and the wave-induced current is negligible in the Hai Phong estuary. The numerical results suggest that the discharge of sediment from some river mouths is the dominant factor to the morphological changes in the high tidal estuary. That might be a main reason for the high turbidity water in the Do Son area.